British oil giant BP has agreed to compensate thousands of victims but many key issues remain unresolved.

Over the course of 87 days, nearly five million barrels of crude oil spewed into the Gulf of Mexico after the Deepwater Horizon rig exploded in April 2010.

The impact on the environment was devastating - both for the people living along the coastline of the Gulf states as well as for the $3bn fishing industry there.

"All along the way BP has done the right thing, has stepped up to the plate. To their credit and to the credit of [all those involved] one will find that everybody gets compensated in a fair manner. It's not that BP has unlimited resources to provide … this was a mistake. This was accidental. This was not purposeful action on their part."

- Randa Fahmy Hudome, a former Halliburton representative

Late last week, the British oil giant BP agreed to pay out an estimated $7.8bn to settle a lawsuit with more than a 120,000 victims of the disaster.

A trial to determine blame has been postponed. But settlements will not be universally welcomed around the Gulf. Many still want to see BP, Transocean and Halliburton held to account in court.

And, whatever the outcome some important issues still remain unanswered.

Firstly, the health impact of the chemical dispersants - more than eight million litres - that were used to break up the oil spill is still unknown.

Secondly, there is the environmental damage. While the oil may have visibly cleared from the Gulf, it may be years before ecologists know the full impact of the spill.

In the immediate aftermath of the disaster Barack Obama, the US president, came out strongly against those involved and stressed the need for reform of the oil industry.

"I will not tolerate more fingerpointing or irresponsibility … yet executives of BP and Transocean and Halliburton are falling over each other to point the finger of blame at somebody else. But it is pretty clear that the system had failed, and it failed badly .… Permits were too often issued based on no more than assurances of safety from the oil companies. That cannot, and will not, happen anymore."

"For volunteers and cleanup workers who came equipped with respirators and breathing devices they were told by BP representatives that if they wear them at the site they will be terminated. We're not talking about a company as it portrays itself for these commercials about wanting to do the right thing, wanting to be accountable."

- Monique Harden, environmental lawyer

But despite Obama's tough talk critics say the US is no more protected today than it was before the BP blowout.

Garret Graves, the chairman of the Coastal Protection and Restoration Authority of Louisiana, described the long-term effects of the spill on the state and its industries, saying:

"Today, Louisiana still has over 20 miles (32 kilometres) of shoreline that are moderately and heavily oiled, and we have nearly 200 miles (322 kilometres) that are still oiled. And here we are approaching two years after the spill and with that type of duration in a very productive ecosystem, the impacts are significant."

For a while Obama's moratorium on drilling reduced oil production in the Gulf of Mexico, but not anymore.

There are now 40 rigs operating in the Gulf today compared with 25 a year ago. BP itself has five of those rigs, the same number it had before the accident. It plans to have a total of eight in the Gulf by next year.

The US energy department estimates that by 2020, oil production will nearly double to two million barrels a day, from its current level of 1.3 million barrels a day.

So, what lessons have been learned from the BP oil spill in the Gulf of Mexico?

Joining Inside Story with presenter Anand Naidoo to discuss this are: Randa Fahmy Hudome, a former representative of Halliburton; Tyler Suitors, a freelance journalist who covered the BP oil spill for the programme Energy Now; and Monique Harden, an environmental lawyer representing several Gulf fisherman.

"The federal oil spill commission appointed by the US president … in its report did say that while we're blaming the companies for this spill much of the blame also lies with us, the government, for lax regulation."

Tyler Suitors, a freelance journalist

What BP's settlement entails:

It gives affected individuals and businesses an estimated $7.8bn but that is not the end to BP's legal woes. The agreement does not include BP's partners Transocean, which owned the doomed Deepwater Horizon oil rig, or Halliburton, which provided the rig with construction materials. The two companies also face possible criminal and civil penalties with an estimated $65bn in long-term cleanup costs.

Those seeking damages from BP and its partners include their investors, the US federal and state governments, and workers who helped clean up the spill. Also, BP, Halliburton and Transocean are suing each other.